1. Field of the Invention
The present invention is related to the area of image display, particularly related to techniques for dynamically regulating brightness of backlighting in display device (e.g., a mobile device, a laptop and a television).
2. Description of Related Art
More and more mobile devices (e.g., a mobile phone, a personal digital assistant (PDA) and the like) can support multimedia functions, such as displaying an electronic book, playing a three dimensional game, viewing pictures or watching a video. Hence, image quality for the display on the mobile devices has become one of the selling factors to gain popularity among consumers.
Brightness exhibited in the real environment has a very broad dynamic range. A visual system in human eyes can only sense the brightness of about five orders of magnitude in the brightness dynamic range of the real environment. A mobile display device generally has lower image contrast and usually cannot be adaptive to the ambient light changes largely due to the limitation in hardware. For example, an image displayed on a mobile phone may be too dark to see the details in the relatively dark areas of the image when in a bright environment such as outdoors with bright sunshine. Furthermore, the liquid crystal material of the display device in a mobile phone cannot block the backlighting completely under the dark environment, so that a dark state light leakage phenomenon may occur in the dark areas of the image to cause the reduction of the image contrast.
A conventional method is to regulate the brightness of the backlighting manually, typically by a user. For example, the brightness of the backlighting in some mobile phones is divided into several levels for the user to adjust. However, such a control manner is troublesome to use. Furthermore, a superior display quality cannot be achieved only by enhancing the brightness of the backlighting in the bright environment. Moreover, the power for the mobile device may not be efficiently used in a dark environment.
Therefore, techniques for regulating the backlighting brightness under all lighting conditions are desired. As such, a mobile display device with a low dynamic range is able to display a high dynamic range and a good visual effect. Further such a mobile display device can save power, thereby prolonging the use of an internal battery.